Eudaemonema webbi sp. nov. (Mammalia, Mixodectidae) from the late Paleocene of western Canada: the youngest known mixodectid

2010 ◽  
Vol 47 (12) ◽  
pp. 1451-1462 ◽  
Author(s):  
Craig S. Scott

Mixodectidae (Mammalia, Archonta) are an unusual, poorly known family of dermopteran-like mammals that have been discovered at several North American localities of primarily early Paleocene age. Among the three or four recognized mixodectid genera, Eudaemonema Simpson is perhaps one of the least understood, being known from only a few localities of late Torrejonian and earliest Tiffanian age. This paper reports on a new species of Eudaemonema from the late Paleocene of Alberta, Canada, that significantly extends the geographic and stratigraphic ranges of the genus. Eudaemonema webbi sp. nov. is known from middle and late Tiffanian localities in central and south central Alberta, and it represents the youngest and northernmost species of Eudaemonema so far discovered. E. webbi differs from the genotypic species E. cuspidata in being larger and in having a suite of dental characters (e.g., molariform posterior premolars, enlarged molar protocone and hypocone, development of a second grinding platform on the lower molars) that suggests an increased emphasis on grinding during mastication. E. webbi possesses several dental features (e.g., broad, shelf-like molar paraconid–paracristid, lingually shifted molar hypoconulid) that resemble those of cynocephalids (Mammalia, Dermoptera), with these resemblances interpreted herein as convergent. The occurrence of E. webbi at Gao Mine extends the stratigraphic range of Eudaemonema into the late Tiffanian (Ti5) and represents the youngest known record of Mixodectidae.

1984 ◽  
Vol 21 (11) ◽  
pp. 1262-1267 ◽  
Author(s):  
Richard C. Fox

Nearly complete lower dentitions (with c?, p2–4, m1–3) and the first discovered upper dentitions (with P2–4, M1–3) are described and illustrated for the late Paleocene primate Micromomys Szalay. These fossils, from the Paskapoo Formation of central Alberta, Canada, represent a new species, the geologically earliest known species of the genus. Micromomys appears to have been a primitive microsyopid most closely related to the early Paleocene Purgatorius Van Valen and Sloan and the middle Paleocene Palenochtha Gidley; a relationship between Micromomys and the early Eocene Tinimomys Szalay may not be as near as previous workers had supposed.Micromomys is the smallest primate known and was probably insectivorous. Its occurrence with the rare European primate Saxonella Russell, a new, primitive carpolestid, and an unusual mammal possibly related to palaeanodonts documents a facies not yet encountered in other Paleocene mammal local faunas, in Canada or elsewhere.


2018 ◽  
Vol 92 (5) ◽  
pp. 896-910
Author(s):  
Craig S. Scott ◽  
Anne Weil ◽  
Jessica M. Theodor

AbstractMultituberculates were among the most taxonomically diverse mammals of the early Paleocene, having survived the catastrophic Cretaceous-Paleogene mass extinction and radiating soon thereafter. Although their evolution during the early Paleocene saw the advent of increasingly specialized dentitions, multituberculates generally remained small, rarely exceeding body sizes greater than those of extant rabbits. A conspicuous exception is the Taeniolabidoidea, a primarily North American clade whose members include the largest multituberculates yet discovered. Taeniolabidoidea includes several genera, with one of these,Catopsalis, being speciose and geographically wide ranging. Until recently, the chronological succession ofCatopsalisappeared to document a trend of increasing body size. We report here on a new species ofCatopsalisfrom the early Paleocene of Alberta that violates this trend and suggests that the evolutionary history ofCatopsalisis considerably more complex.Catopsalis kakwanew species is not only the smallest species ofCatopsalis, but is the smallest taeniolabidoid so far discovered, with an estimated body mass between 400 g and 660 g. In contrast to previous studies, we used recently proposed regressions based on lower cheek tooth row length to estimate body masses for North American taeniolabidoids. Our results propose more modest body mass estimates, particularly for the largest taeniolabidoids. The occurrence ofC.kakwan. sp. in the late early Paleocene implies either a significant ghost lineage, or reversal of several characters, including body size, during the latter part of the early Paleocene; the more likely of these scenarios must await a better understanding of the phylogenetic position ofC.kakwan. sp.UUID:http://zoobank.org/66d85345-49b8-4a46-ba6e-a4d4369cb3e0urn:lsid:zoobank.org:pub:AF7A5659-9068-4F2F-A6EC-5522A2BBA4CB


1961 ◽  
Vol 93 (6) ◽  
pp. 450-455 ◽  
Author(s):  
Leonard A. Kelton

Recent study of the male genitalia in the Miridae (Kelton, 1959) showed that the Palearctic Stenodema virens (L.) does not occur in North America. The six other species that have been reported in the North American literature are: dorsolis (Say), vicinum (Prov.), trispinosum Reut., sequoiae Bliven, falki Bliven, and imperii Bliven. The three species described by Bliven (1955, 1958) were not available to me for study, however, Bliven (1960) has recently published a paper containing figures of the male genital claspers of these species. These appear to differ considerably from those of virens, vicinum and trispinosum as well as amongst themselves.


1998 ◽  
Vol 72 (3) ◽  
pp. 473-476 ◽  
Author(s):  
Joyce C. Grier ◽  
James W. Grier

A third known specimen of the ammonite Rhaeboceras burkholderi Cobban, 1987, has been discovered in the upper part of the Pierre Shale of early Maastrichtian age (Late Cretaceous) Baculites eliasi zone of Dawson County, Montana. This finding extends both the geographical and stratigraphic ranges of the species. In addition, R. cedarense new species is described from the Baculites baculus/grandis zone of the same region, which extends the stratigraphic range of the genus as currently recognized. The new species is a small form of Rhaeboceras that appears to be closely related to and probably descended from R. burkholderi.


2014 ◽  
Vol 51 (12) ◽  
pp. 1059-1066 ◽  
Author(s):  
Richard C. Fox ◽  
Brian D. Rankin ◽  
Craig S. Scott ◽  
Arthur R. Sweet

Pandemonium hibernalis sp. nov., from a middle? Puercan (earliest Paleocene) locality in the upper Scollard Formation, Wintering Hills, southern Alberta, represents the second discovered occurrence of the enigmatic plesiadapiform primate Pandemonium Van Valen and the first from Canada. The holotype of Pandemonium hibernalis is the only known specimen of Pandemonium documented by multiple teeth from a single individual. Pandemonium hibernalis closely resembles the type species Pandemonium dis from Purgatory Hill, middle–late Puercan, Tullock Formation, Montana, but differs in having wider, more bunodont lower molar crowns and a more expanded posterior talonid lobe of m3, specializations suggesting enhanced capacity for crushing and grinding of soft food materials during mastication. Pandemonium hibernalis joins other recent discoveries in Alberta and elsewhere in the North American Western Interior in documenting a moderate radiation of basal plesiadapiforms that evolved unexpectedly early during primate evolution.


1995 ◽  
Vol 8 (6) ◽  
pp. 1035 ◽  
Author(s):  
LJ Scriven ◽  
RS Hill

The oldest known Casuarinaceae macrofossils, from late Paleocene sediments at Lake Bungarby in New South Wales, are assigned to a new species of Casuarinaceae, Gymnostoma antiquum. The nearest living relatives of this species are the Papua New Guinean Gymnostoma species and in particular one as yet unnamed species. Previous problems relating to the preparation, identification and description of Casuarinaceae macrofossils are examined and clarified. The ecology of both living Gymnostoma and G. antiquum are discussed. The decrease in catastrophic disturbance and climate seasonality during the Cenozoic were probably major contributing factors leading to the current distribution of Gymnostoma.


Sign in / Sign up

Export Citation Format

Share Document